Railway-traffic-controlling apparatus



Dec. 24, 1929. A. J. SORENSEN RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 28, 1927 Bmke Control III m a w a m m. .m, 2 T W P .W m w E F M .w. 2 n V .Z I: i l .1 1 E w PN O m ufiwt MKB QQQ S Q UB W w w w w m Pipe. INVENTOR A. J. $o1- ns an,

57 QR-YLEWQJQ Patented Dec. 24, 1929 UNETED sra'rss PATENT OFFICE .ANDREVT J. SORENSEN, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH &, SIGNAL CQIYZPANY, OF SWISSVALE, PENNSYLVANIA, A CQRPORATION OF PENNSYLVANIA RAILWAY-TRAFFIC-CONTROLLING APPARATUS Application filed September 28, 1927.

My invention relates to railway traffic controlling apparatus, and particularly to apparatus of the intermittent inductive type involving inductors located at intervals n the trackway and controlled by trafi ic conditions in advance for transmitting train governing impulses to moving trains.

The present application is a cont nuation in part of my copending ELPPlICZLtlOD filed July 21, 1927, Serial No. 207, lO1, for railway trafiic controlling apparatus, in so far as the subject matter common to the two is concerned.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, big. 1 is a diagrammatic View showing one form of apparatus embodying my invention. F1gs. 2 and 3 are curves showing the magnetic and electrical characteristics of certain parts of the apparatus shown in 1. Fig. 4 s a diagrammatic view showing a modincation of the apparatus shown in Big. 1 and also embodying my invention.

Similar reference characters refer to similar parts in Figs. 1 and 4.

Referring first to F 1g. 1, the reference character A designates amagnetizaole receiver located on a railway train and provided with a primary winding P and a secondary winding S. The train-carried apparatus also includes a relay G, an impedance C which as here shown is a magnet winding C, and a manually operable acknowledging switch K comprising two normally open contacts 12 and 16.

The primary winding P is provided with a circuit which passes from a battery H or other source of direct current, through wires 2 and 3, contact 4 4 of relay G, wire 5, primary winding P, wire 6, magnet w nding C, and wire 7 to battery H. The circuit for the secondary S is from battery H, through wires 2 and 3, contact 4:4t of relay G, wire 8, winding of relay G, wire 9, secondary winding S and wire 10 to an intermediate oint in primary winding P, then through the right-hand portion of the primary winding, wire 6, magnet widing G, and Wire 7 Serial No. 222,520.

to battery H. These circuits are normally closed, with the result that magnet winding C is energized. Vinding C controls a valve -D, which in turn controls the exhaust of air Y phere, and the resultant reduction of pressure in pipe E will then cause an automatic application of the breaks by virtue of suitable apparatus not shown in the drawing.

Located in the trackway are a plurality of inductors B, only one of which is shown in the drawing. Each of these inductors is provided with a winding L, the circuit of which may be opened and closed by a contact 18, which contact is usually controlled in accordance with traffic conditions in advance. The inductors B co-operate with the traincarried receiver A in such manner that if the circuit for winding L is closed when the receiver passes over the inductor the reluctance of the receiver is not materially reduced, whereas if the circuit for winding L is opened, the reluctance of the receiver A is materially reduced, due to the fact that the inductor substantially completes the magnetic circuit of the receiver.

The operation of the parts of the apparatus thus far described, is as follows: Normally, the primary and secondary circuits of the train-carried apparatus are closed, so that magnet C is energized and valve D is closed. lVhen the receiver passes over a tracliway inductor, if contact 18 is closed the reluctance of the receiver core is not materially changed and no change occurs in the condition of the train-carried apparatus. If, however, contact 18 is open, the flux in the receiver core due to the primary winding P is momentarily increased, and this momentary increase of flux creates in the secondary winding S an electromotive force which opposes the electromotive force of battery H. As a result there is produced, in the secondary circuit, a current impulse which opposes the current flowing in the secondary circuit from bat tery H, so that relay is de-energized, with .no action. If the trackway contact 18 is opened, and if the engineer closes the acknowledging switch K just before the receiver passes over the inductor, an auxiliary circuit for relay G will be closed, which circuit passes from battery H, through wires 2 and 15, contact 16 of acknowledging switch K, wire 17 winding of relay G, wire 9, second 'Jary winding S, wire 10, right-hand section (bf-primary winding P, wire 6, magnet U and wire 7 to battery H. Then when the receiver passes over the inductor, relay G will momentarily open but will immediately close again because of the auxiliary circuit which I have just traced. The result will be that valve D remains closed and no automatic application of the brakes occurs. Acknowledging switch K will usually be controlled in such manner that its contacts can be closed only for a limited period of time. If the engineer ails to close acknowledging switch K just before passing over the trackway inductor, and if contact 18 is opened so that an automatic application of the brakes occurs, relay G can be again closed by manual operation of acknowledging switch K. The resulting closure of contact 16 will close the auxiliary circuit for relay G, and the closure of contact 12 will close the following circuit for primary winding P: from battery H, through wires 2 and. 11, contact 12 of acknowledging switch K, resistance 13, wires 14 and 5, primary winding l wire 6, magnet C and wire 7 to battery H. Magnet C and relay G will therefore become re energized, and after relay G closes, these parts continue energized over their normal circuits above described, even though switch K is restored to the position in which it is illustrated in the drawing. The brakes can then be released by suitablemanipulation of the apparatus controlled by pipe E.

With the apparatus thus far described, the receiver and the relay are more sensitive, that is, they are more easily operated upon pass ing inductors and other iron structures, directly after a re-set than after the receiver has passed a few inductors or other iron structures without de-energization of the re- 'lay This is due to hysteresis in the iron cores of the receiver and the relay, and the purpose of the present invention is to pro 'ide means by which this effect of the hysteresis can be eliminated.

--de energ ized by an active trackway inductor,

andthat {the-engine equipment is about to :be

re-s-et. Referring now to Fig. 2, since the receiver comprises a magnetic circuit with an air gap, the flux in the receiver core is always built up in the same way at re-set, namely, from a value very close to zero, rep resented by the point- O, to a value represented by the point F corresponding to the number of ampere turns used to energize the receiver. li fith the flux at the point F 1 will assume that the receiver passes over an inductor in active condition, but that the engineman closes circuit controller K. As the receiver runs into its position in closed relation to the inductor, the receiver flux will increase to a value such as F and when the receiver recedes from such position, the flux will not decrease to the value F but due to the magnetic hysteresis of the iron, it will decrease to a value F whichis greater than F If the receiver then passes another in ductor under the same conditions, the flux will increase to a value F which is slightly greater than the value F and will then decrease to a value slightly greater than F This process will be repeated every time an inductor is passed under the same conditions,

except that the values within the groups F and F respectively, will tend to reach limiting values so that finally a point will be reached at which the flux will change between the $211116 two values every time. The same action will result from inductors in the inactive condition, or from switch rails or other masses of iron located close to the path of the receiver A. As pointed out in describing the normal operation of the apparatus, an increase in the flux in the receiver A induces a voltage in the secondary winding S, which is in opposition to the normal voltage applied to the secondary circuit by battery H, this opposing voltage at a given speed being very nearly proportional to the increase in the flux in the receiver core. Still referring to Fig. 2, it will be seen that the distance (Z representing the increase in flux caused by the second inductor, is shorter than the distance 6Z1, representing the increase of flux caused by the first inductor. Similarly, the increase of flux due to passing further successive inductors will be successively less until the point is reached at which the flux changes between the same two values each time. It is evident, therefore, that the .op posing voltage induced in the secondary winding at a given speed, due to passing an active inductor, is greatest directly after the train-carried apparatus has been re-set. The operation of the valve magnet C by an active inductor depends on the reduction in the current in relay G due to the voltage induced in the secondary winding S. For example, if the holding current through the relay G is 'millia-mperes and the relay releases at 20 milliamperes, the reduction in current in the secondary circuit due to the receiver passing normal clearance between receiver and inductor and with normal voltage applied to the traincarried circuits. If this minimum speed is 1.5 miles per hour, then the equipment should always operate to cause a brake application when passing an active incuctor at a speed higher than 1.5 miles per hour, but not at a lower speed. This condition of the equipment, however, is affected by hysteresis in two ways. In the first place, assuming that the adjustment of the equipment is made by running over a stop inductor a number of times until it is ascertained that 1.5 miles per hour is the critical speed at which the equipment will operate, then if all engines after adjustment are to be in the same condition, it is evident that tl e adjustment runs must be made in the same way for all engines. If one engine is adjusted by running over an induct-or a number of times, increasing the speed every time the equipment d es not operate, until it finally operates at a speed slightly above the critical limit, and if another engine is adjusted by the reverse pro cedure, that is, starting with speeds above a critical limit and allowing the equipment to operate at every inductor until a value slightly below the critical limit is reached, then it is evident that on account of the hysteresis cried; the two engines will show diii erences in operation when given speed tests under conditions that are actually identical so far as hysteresis is concerned. Consequently, in order to obtain uniform performance on all engines, it is necessary to specify a definite procedure for the adjustment of the engine equipments, so that the receiver will always be in the same hysteresis condition. A considerable number of test runs may be neces sary, however, because at low speeds it is difficult to control the engine speed accurately, and if operations must be added to insure a uniform hysteresis condition of the iron in the engine equipment, the process of adjusting the engine equipment is one which corn sumes considerable time and requires careful attention. In addition to the foregoing, and assuming that uniform adjustment is obtained on all engines, it follows by reference .to Fig. 2 that each equipment will be more sensitive to inductors directly after re-set than after passing one or more inductors without being de-energized. Since it is necessary to insure that the equipment under adverse conditions, such as high train voltage and excessive clearance, will not fail to operate at high speeds, and since on the other hand undesired brake applications due to rails, frogs, etc must be kept at a minimum, it is readily seen that the hysteresis effect acts to reduce the margin of operation.

The above discussion, although applied saecifically to the receiver core, applies also to the relay G. The effect in the relay is more complicated, but the result is of the same nature as the result of the elfect in the receiver core. As stated hereinbefore, the relay current diminishes in response to an increase in receiver flux, and, conversely, it increases in response to a decrease in receiver flux. Therefore, every time the receiver runs past an inductor or other iron structure without causing the relay to release, there is first a decrease in the relay flux and then a momentary increase above the normal value. The result of this is a gradual increase in the flux normally present in the relay core, and, consequently, after passing a number of inductors the relay will require a larger reduction in current in order to become de-energized, than immediately after a re-set. The effect on the sensitiveness of the equipment as a whole is smaller than the effect due to hysteresis in the receiver core, but is quite perceptible.

To eliminate these hysteresis effects, I propose to arrange the apparatus so that the iron structures are always in the same l1ysteresis condition. this being the condition which obtains after the train has passed a few inductors. so that a steady condition in the iron has been reached. To accomplish this, I provide a shunt of relatively low impedance around the magnet C, this shunt comprising an impedance 19 and a normally open contact M which may be closed manually by the engineer or other individual on the engine. When the apparatus is re-set after a brake application, and relay G has closed, the engineer closes switch M for about one second and then opens it again before switch R returns to its normal position. Before the switch M is closed, the flux in the receiver core is at the value represented by the point F in 2, but upon closing the switch M the primary current increases to a value suflicient to produce a flux corresponding to the point F or a somewhat higher flux, so that the iron is practically in its stable condition and the sensitiveness of the equipment will not change upon passing the next inductor. Considering the relay G, before closing switch M the current flowing through the relay winding is normal, and since the closing of switch M causes a large increase in the receiver flux the relay will release, but, since contact 16 of switch K is now closed, the excess voltage of the auxiliary circuit will immediately close the relay again. When switch M is opened, a considerable reduction in the receiver flux occurs, inducing a momentary excess current in the relay coil, thus increasing the amount of flux normally present in the relay core and bringing the relay into the same operative condition as that caused by passage of the equipment over several inductors or other iron structures.

"It follows that when switch M has been closed and is again opened, the equipment is in a condition which is not changed by anything that happens during operation, except by an active trackway inductor. Switch M should be usedeverytime the equipment is re-set, and while the equipment is being 'tested, but at no "other time. If closed accidentally, it will cause the valve magnet to release and so'thebrakes will be applied.

The'value of the impedance 19 will depend upon the density of flux in the receiver, and other factors-so that it must be determined experimentally for equipments having di'iier- -ent characteristics. 1 have tound'that in one commercial form of train control equipment, i fthe value of the impedance 19 is zero, only a smallbver-correction of the hysteresis conditions will result.

Referring now to Fig. i, the apparatus shown in this view is the same as that shown in Fig.1, except as to the means for controlling the low in'ipedance shunt around the magnet winding C. In Fig. 4, the manually operable switch M has been omitted, and this shunt is controlled by an additional contact "22 on the acknowledging switch K. The low impedance shunt is further controlled by an auxiliary relay R having a back contact 20 and a trout contact 21. V

' VViththe parts in their normal conditions, as "shown in the drawing, that is, with relay G and magnet winding G both energized, a first shunt around magnet winding G is closed, which shunt passes from wire '6, through wire 23, winding of relay R, back contactQQ-QQ -'on -a"cknowledging switch K, impedance 19, and wire 24 to wire 7 The proportioning of the parts is such that relay ER is then energized, but the resistance of this relay is so high that the shunt path which has just been traced takes an inappreciable amount of current. When the receiver A 'p'asses over a trackway inductor B, if contact 18 is closed, the train carried apparatus is not "affect-ed in any way. It contact 18 is opened, however, and the engineer acknowledges by operating tl i'e acknowledging switch K, auxiliary relay R remainsenergized because front contact 21 of this relay is connected in multiple with contact 22-'2 2 so that the opening of the latter contact does not open the circuit for re-lay R. If the-engineer does not acknow-ledge, however, the opening of relay G will open the circuits for magnet winding G and for relay R, so that the latter relay will become de-ehergize'd. lV-hen the engineer operates the acknowledging switch K to again pick up relay Gr, a shun-tot low impedancewill be closed around magnet winding G which shunt passes from wire 6, through wire'28, back contact 20 of relay R and the normally open contact -2222 on acknowledging switch K, impedance 19 and wire 24: to wire 7. It will be noted that this path does not include the winding of relay R, and, consequently, the shunt path just traced momentarily increases the magnetic flux'in the receiver A, and therefore restores this receiver to its normal hysteresis condition. hen the acknowledging switch K returns to its normal position, relay R again closes and all parts of the apparatus again occupy the positions in which they are shown in the drawing.

As stated in connection with Fig. 1, the value of the impedance 19 will depend on various factors, and may in some instances be zero.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a train control system of the type comprising a magnetizable receiver on the train, a primary winding and a secondary winding on said receiver, a circuit for said primary winding including a. source of direct current and an impedance, a circuit for said secondary winding including a source of direct current, inductors located in the trackway for cooperation with said receiver, and train governing means controlled by said secondary circuit; the combination with the foregoing instrumentalities of a normally open shunt of relatively low impedance around said impedance in said primary circuit, for eliminating the effect of hysteresis in the core of said receiver, and manually operable means for closing said shunt.

In a train control system of the type comprising a magnetizable receiver on the train, a primary winding and a secondary winding on said receiver, a circuit for said primary winding including a source of direct current and an impedance, a circuit for said secondary winding including a source of direct current, inductors located in the trackway for co-operation with said receiver, and train governing means controlled by said secondary circuit; the combination with the foregoing instrumentalities of manually operable means located wholly on the train for momentarily increasing the magnetic flux in said receiver and thereby eliminating the etfoot of hysteresis in the core of said receiver.

3. In a train control system of the type comprising a magnetizable receiver on the train, a primary winding and a secondary winding on said receiver, a relay,a circuit for said primary winding including a source of direct current and a front contact of said relay and a magnet winding, a circuit for said secondary winding including the winding of said relay as well as a front contact of the relay and a portion of said primary winding and said magnet winding, inductors located in the trackway for cooperation with said receiver, and train governing means controlled by said magnet winding; the combination with the aforesaid instrumentalities of a normally open shunt of relatively low impedance around said magnet winding, and manually operable means for closing said shunt.

4. In a train control system of the type comprising a megnetizable receiver on the train, a primary winding and a secondary winding on said receiver, a relay, a circuit for said primary winding including a source of direct current and a front contact of said relay and a magnet winding, a circuit for said secondary winding including the winding of said relay as well as a front contact of the relay and a portion of said primary winding and said magnet winding, inductors located in the trackway for co-operation with said receiver, and train governing means controlled by said magnet winding; the combination with the aforesaid instrumentalities of manually operable means wholly on the train for momentarily increasing the magnet flux in said receiver.

5. In a train control system of the type comprising a megnetizable receiver on the train, a primary winding and a secondary winding on said receiver, a circuit for said primary winding including a source of direct current and an impedance, a circuit for said secondary winding including a source of direct current, inductors located in the trackway for co-operation with said receiver, and train governing means controlled by said secondary circuit; the combination with the foregoing instrumentalities of a manually operable circuit controller having a normally closed contact and a normally open contact, an auxiliary relay having front and back contacts, a shunt path around said impedance including the winding of said auxiliary relay and said normally closed contact, and a second shunt path around said impedance including a back contact of said auxiliary relay and said normally open contact.

6. In a train control system of the type comprising a magnetizable receiver on the train, a primary winding and a secondary winding on said receiver, a circuit for said primary winding including a source of direct current and an impedance, a circuit for said secondary winding including a source of direct current, inductors located in the trackway for co-operation with said receiver, and train governing means controlled by said secondary circuit; the combination with the foregoing instrumentalities of a manually operable circuit controller having a normally closed contact and a normally open contact, an auxiliary relay having front and back contacts, a shunt path around said impedance including the winding of said auxiliary relay and said normally closed contact, a second shunt path around said impedance including a back contact of said auxiliary relay and said normally open contact, and a branch for said first shunt path around the normally closed contact said branch including a front contact of said auxiliary relay.

7. In a train control system of the type comprising a magnetizable receiver on the train, a primary and a secondary winding on said receiver, a main relay, a circuit for said primary winding including a. source of direct current and a front contact of said relay as well as a magnet winding, a circuit for said secondary winding including the winding of said relay as well as a front contact on said relay, and train governing means controlled by said magnet winding; the combination with the aforementioned instrumentalities of manually operable means wholly on the train for momentarily increasing the magnetic flux in said receiver and thereby eliminating the effect of hysteresis in the cores of said receiver and said relay.

In a train control system of the type comprising a magnetizable receiver on the train, a primary and a secondary winding on said receiver, a main relay, a circuit for said primary winding including a source of direct current and a front contact of said relay as well as a magnet winding, a circuit for said secondary winding including the winding of said relay as well as a front contact of said relay, train governing means controlled by said magnetwinding, and an acknowledging switch having normally open contacts con nected in shunt around the front contacts of said main relay in the circuits for said primary and secondary windings; the combination with the aforementioned instrumentalities of means controlled by said acknowledging switch when operated to close its normal ly open contacts for momentarily increasing the magnetic flux in said receiver and thereby eliminating the effect of hysteresis in the cores of said receiver and said main relay.

9. In a train control system of the type comprising a megnetizable receiver on the train, a primary and a secondary winding on said receiver, a main relay, a circuit for said primary winding including a source of direct current and a front contact of said relay as well as a magnetic winding, a circuit for said secondary winding including the winding of said relay as well as a front contact of said relay, train governing means controlled by said magnet winding, and an acknowledging switch having normally open contacts connected in shunt around the front contacts of said main relay in the circuits for said primary and secondary windings; the

combination with the aforementioned instrumentalities of additional normally closed and normally open contacts on said acknowledging switch, an auxiliary relay having front and back contacts, a shunt path around said magnet Winding including the winding of said auxiliary relay and said additional normally closed contact, a second shunt path aroundsaid magnet Winding including a backcontact of said auxiliary relay and said additional normally open contact, and a branch for said first shunt path around the normally closed acknowledging switch contact therein, said branch including a front Contact of said auxiliary relay.

10. In a traincontrol' system of the type comprising a magnetizable receiver on the train ce-operating with trackway inductors,

the combination therewith ofmeans located Wholly on the train tormomentarily increasingthemagnetic flux in said receiver and thereby eliminating the effect of hysteresis in the core of the receiver.

11. In a train control system of the type comprising a magnetizable receiver on the train, a winding on said receiver, and a circuit including said Winding and asource of current as well as a train governing device, the combination therewith of means located wholly on the train for momentarily increasingthe magnetic flux in said receiver and therebyeliminating' the effect of hysteresis in the core of the receiver.

Intestimony whereof- I afiix my signature.

ANDREW J. SORENSEN. 

